Safety teeter-totters



March 12, 1957 w. M. BAKULA 2,784,968

SAFETY TEETER-TOTTERS Filed July 18, 1955 INVENTOR. Man-w /7, 54/0/04 mar 4 United States Patent SAFETY TEETER-TOTTERS Walter M. Bakula, Denver, Colo. Application July 18, 1955, Serial No. 522,704 3 Claims. (Cl. 272-54 This invention relates to a childs amusement device of the type usually designated as a teeter-totter and has for its principal object the provision of a safety device which will prevent the teeter-totter board from moving faster than a pre-set safe speed.

Children are often injured on teeter-totters due to a child at the lower end of the board either jumping or falling from the board so as to allow the child at the higher end of the board to drop with damaging results. This invention is designed to provide a safety control device or governor which, will act, if the lower extremity of the board is released when the higher extremity is loaded, to apply a braking action which will allow the loaded extremity to descend at a safe speed so as to prevent injury to the child thereon.

Another object of the invention is to so construct the improved teeter-totter safety device that it can be quickly and easily applied to any of the conventional teeter-totter boards.

Other objects and advantages reside in the detail construction of the invention, which is designed for simplicity, economy, and efliciency. These will become more apparent from the following description.

In the drawing:

Fig. 1 is a side elevation of a conventional teeter-totter with the invention applied thereto;

Fig. 2 is a left end view of the device of Fig. 1;

Fig. 3 is a right end view thereof;

Fig. 4 is an enlarged, detail, cross-section, taken on the line 4-4, Fig. l; and

Fig. 5 is a detail, longitudinal section through a shock absorbing device of a type employed in the invention.

In the drawing, a conventional teeter-totter board is illustrated at mounted by means of bearing members 11 upon a horizontal cross bar 12. The cross bar may be supported in any desired manner such as by means of suitable pipe fittings 13 supported upon tubular, flaring supporting legs 14. The method of mounting and supporting the teeter-totter board 10 is simply illustrative, as the board may be supported in any conventional manner.

The improved safety device or governor comprises a semi-circular, flanged brake drum 16 which is secured to the mid-portion of the board 10 about the cross bar 12 in any desired manner, such as by means of suitable attachment bolts 17, so as to extend downwardly from and below the board 10 with its flange positioned concentrically about the axis of the cross bar 12.

A cross brace bar 15, carrying an attachment bracket 19, is welded or otherwise secured between two opposite legs 14. An elongated leaf spring 18 is secured at its one extremity to the attachment bracket 19 in any desired manner, such as by means of bolts 20. The leaf spring 18 extends beneath the brake drum 16 and terminates at its other extremity in a hinge pin 21 to which the plunger 22 of a shock absorbing cylinder 23 is secured. The shock absorbing cylinder may be a conventional 2,784,968 Patented Mar. 12, 1957 vehicle shock absorber of a type to allow the plunger to move freely at speeds below a pre-set speed and to resist movement of higher speeds. A shock absorber of this type is illustrated in Fig. 5 in which the cylinder 23 contains a piston 32 to which the plunger 22 is secured. The piston is provided with by-pass passages 33 through which hydraulic fluid may flow as the cylinder moves upwardly and downwardly relative to the piston 32. Since the fluid can only pass at a predetermined rate, determined by the size of the by-pass passages, additional force applied will tend to cause the piston 32 to move with the cylinder 23.

The shock absorbing cylinder 23 is suspended at its upper extremity from a hinge pin 24 mounted in suitable attachment brackets 25 bolted beneath the board 10 by means of suitable attachment bolts 26.

A channel-shaped brake shoe member 27 is secured on the leaf spring 18, at the point where the latter passes beneath the brake drum 16, by means of suitable cap screws 28, or in any other desired manner. The channelshape of the brake shoe provides an upper braking portion 29 above the flange of the drum 16 and a lower braking portion 30 below the flange of the drum 16. Each braking portion is provided with a suitable brake lining The linings 31 are normally spaced apart sufliciently so as not to engage the flange of the brake drum 16. However, if the extremity of the leaf spring 18 is forced upwardly, the lining on the lower brake portion 30 will frictionally engage the flange of the brake drum and retard movement. If the extremity of the leaf spring 18 is forced downwardly, the lining on the upper brake portion 29 will frictionally engage the flange of the brake drum 16 and retard movement.

The upward and downward movements of the leaf spring 18 are instigated in consequence of the relative movement of the shock absorbing cylinder 23 about the piston 32. Let us assume that there are two children on the board 10 and that the left extremity is elevated. Now let us assume that the child on the right extremity leaves the board. The other child will start to descend, causing the absorbing cylinder 23 to tend to descend over the piston 32 at a faster rate than the fluid can flow through the by-pass passages 33 so that the piston 32 will be forced downwardly. This causes the plunger 22 to force the leaf spring 18 downwardly so as to bring the upper braking portion 29 of the brake shoe 27 into frictional engagement with the flange of the brake drum 16 so as to retard the descending motion to a safe speed.

It can be seen that a similar action takes place should the right extremity of the board be in the elevated position and suddenly released. In the latter case, the shockabsorbing cylinder 23 will be urged upwardly to lift the extremity of the leaf spring 18 so as to bring the lower braking portion 30 of the shoe 27 into frictional engagement with the flange of the drum .16 so as to retard the descending speed.

For all normal teetering speeds, the piston 32 will remain stationary and the hydraulic fluid will simply flow back and forth through the piston. While the device has been described as using hydraulic fluid in the cylinder 23, it is conceivable that the same results could be obtained with the use of air as the fluid medium.

An L-shaped clip 34 is attached to the leaf spring 18 by means of the bolts 28. The clip 34 extends upwardly and engages the drum 16 to prevent the brake shoe member 27 from being forced sidewardly therefrom.

While a specific form of the improvement has been described and illustrated herein, it is desired to be understood that the same may be varied, within the scope of the appended claims, without departing from the spirit of the invention.

Having thus described the invention, what is claimed and desired secured by Letters Patent is:

1. A safety device for a teeter-totter board having a medially positioned supporting structure comprising: an arcuate brake drum secured to said board at its tilting axis; a horizontally projecting peripheral flange on said brake drum; a channel-shaped brake shoe arranged to extend above and below said flange; a lever member afiixed to and supported at its one extremity from said supporting structure and being secured intermediate its extremities to said brake shoe; and a shock absorbing device secured between said board and the other extremity of said lever member and adapted to impart movement to said lever member in consequence of rapid movement of said board.

2, A safety device for teeter-totter boards as described in claim 1 in which the shock absorbing device comprises: a fluid cylinder; means securing said cylinder to said board; a piston in said cylinder; at plunger securing said piston to the said other extremity of said lever member; and means for allowing fluid to by-pass said piston at a predetermined rate of speed.

3. A safety device for a teeter-totter board as described in claim 1 in which the lever member comprises a flexible leaf spring, said spring having a shape to normally maintain said channel-shaped brake shoe out of contact with said flange.

References Cited in the file of this patent UNITED STATES PATENTS 2,236,409 Lanman Mar. 25, 1941 

